Food packaging is one of the most commonly used materials today due to its affordability and convenience. However, this type of packaging is challenging to handle after use, leading to significant environmental waste since it is often made from petrochemical polymers that take a long time to decompose. Polyvinyl alcohol (PVA) is a low-cost, safe, and biodegradable polymer with high potential for food packaging, offering a solution to waste issues in the polymer industry. However, its limited hydrophilicity, bactericidal properties, and poor performance in humid conditions hinder its practicality. Enhancing the mechanical properties and water resistance of PVA-based composite films can significantly improve their applicability, particularly in food packaging. In this study, nanocomposite films based on PVA were reinforced with nanocellulose fiber (CNF) and Ag nanoparticles (AgNPs), and cross-linked using citric acid (CA) through the film casting method. The incorporation of CNF and AgNPs improved the structural integrity and thermal stability of the film, while CA crosslinking significantly enhanced water resistance and mechanical properties. The (PVA/CNF/Ag)-CA film exhibited the highest tensile strength (89.44 MPa), Young's modulus (3.29 GPa), and water contact angle (similar to 90 degrees), alongside the lowest water absorption (78.6 %) and a reduced water vapor transmission rate of 6.62 g x h(-1) x m(-2). Compared to pure PVA film, the resulting crosslinked nanocomposite films showed a 32.3 % increase in modulus and a 22.64 % increase in tensile strength. Additionally, the (PVA/CNF/Ag)-CA film exhibited higher thermal stability with 13 % more residue content than uncrosslinked counterparts, reduced moisture absorption, minimal swelling, and water insolubility. However, the CA crosslinking process promoted AgNP aggregation, reducing the antibacterial activity of the (PVA/CNF/Ag)-CA film against Staphylococcus aureus and Escherichia coli, and slowed down its biodegradation in soil. Nevertheless, after seven days of storage under both aerobic and anaerobic conditions, the nanocomposite coatings effectively minimized mass loss and microbial growth on fresh chili peppers. These results highlight the synergistic contribution of CNF/Ag reinforcement and CA crosslinking in enhancing the mechanical strength, thermal stability, and water resistance of PVA-based films for potential food packaging applications.

Environmental issues caused by plastic films promote the development of biodegradability packaging materials. Copper ion-modified nanocellulose films were prepared through a one-pot reaction and systematically investigated their structural characteristics, thermal stability, mechanical properties, antibacterial activity, and biodegradability. The results indicate that the film prepared by co-soaking CNCs and copper in NaOH solution for 12 h has favorable performance. Introduction of copper ions as crosslinkers increases tensile strength of film from 36.8 MPa to 56.4 MPa and water contact angle of film from 46 degrees to 92 degrees. Copper coordination also endows the film excellent antibacterial activity, inhibiting growth of Escherichia coli and Staphylococcus aureus. Moreover, biodegradability tests indicate that although the introduction of copper ions slightly reduce biodegradation rate of films, they could still be decomposed significantly within four weeks as burying in soil. This simple process for preparing cellulosic films with water resistance, thermal stable, antibacterial ability, and biodegradable shows potential application in flexible packaging film.

There is currently a growing interest in biopolymers, such as bacterial cellulose and thermoplastic starch, which are renewable and abundantly available in nature. This study investigated the multilayer sandwich composite with thermoplastic starch and bacterial cellulose, using water (TPS/BC-w) and glycerol (TPS/BC-g) as coupling agents. The composites produced by compression molding resulted in a homogeneous, transparent and flexible structure. TPS/BC-w showed superior mechanical property and better adhesion compared to TPS/BC-g. Therefore, the permeability, biodegradation, hydrothermal aging and stability analyses were conducted only for TPS/ BC-w. The water vapor permeability of TPS/BC-w is 6.7 times lower than that of thermoplastic starch, indicating better barrier performance. Thermoplastic starch and bacterial cellulose degraded in about 9 days, and TPS/BCw degraded in 60 days. Biodegradation analysis by COQ release confirmed the complete biodegradation process, with COQ emissions of 57 %, 42.5 % and 39.6 % after 120 days for thermoplastic starch, bacterial cellulose and TPS/BC-w, respectively. TPS/BC-w remained intact for more than a year, in an environment without direct contact with soil or water. These results indicate that TPS/BC-w composed of natural macromolecules may exhibit functional properties and is useful for applications such as short-shelf-life packaging, particularly for dry products, due to its barrier properties and controlled biodegradability.

Herin, a biodegradable bioplastic composite packaging film was prepared by utilizing bamboo powder partially in replace of plastic. Bamboo powder lignocellulose and polybutylene adipate terephthalate (PBAT) resin granules were mixed together with certain percentage to form bamboo-plastic complex, and then through hotpressed to obtain the bamboo/PBAT bioplastic composite films. The effect of bamboo powder content on overall properties of the composite film was systematically investigated. Results showed that the addition of bamboo powder could greatly improve the mechanical properties of composite films, especially the tensile strength and elastic modulus increased by 18.90 %, 251.58 %, respectively. Besides, the bioplastic composite film exhibited superior water resistance including the high water contact angle value of 108.13 degrees, low water absorption rate (2.38 %), and water absorption thickness expansion rate (1.08 %) with 10.0 % bamboo powder content. Notably, the enhanced bonding between bamboo powder and PBAT contributed to the excellent gas barrier performance (1.48 x 10- 2 cm3 & sdot;m/(m2 & sdot;24 h & sdot;0.1 MPa)). With the increase of bamboo powder addition, the melt flow rate of the composite was increased, indicating the improved processing performance. More importantly, the bamboo/PBAT bioplastic composite film showed good packaging preservation ability for strawberry and excellent biodegradability in soil, presenting feasible and green alternatives to biodegradable plastic food packaging material.

All-cellulose composites (ACC) are reinforced and impregnated entirely with cellulose. In this study, ramie (Boehmeria nivea) was used as reinforcement materials because of their excellent mechanical properties and then combined with luffa (Luffa cylindrica) cellulose as the matrix to fabricate ACC with the conventional impregnation method (CIM). The NaOH/urea solution was selected to dissolve luffa cellulose. Epichlorohydrin (ECH) was added to the cellulose solution as a crosslinker for hydrogel formation. Scanning electron microscope (SEM) was conducted to evaluate the interaction between ramie fibers and luffa matrices. The mechanical properties, density, and wettability were evaluated by varying the fiber mass fraction. The results showed that ACC from ramie-luffa had a tensile strength of 35.13 MPa at a high fiber fraction, a density under 1.3 g cm-3, and an average contact angle of up to 92.1 degrees. Soil-burial testing was conducted to approach the degradability of the ACC. The results demonstrated that the degradation of ACC reached 64.41 % after 28 days of burial in the soil. These findings suggest that ACC from ramie and luffa holds significant potential as a sustainable and environmentally friendly composite.

Bacterial cellulose (BC), known for its exceptional physical properties and sustainability, has garnered widespread attention as a promising alternative to petrochemical-based plastic packaging. However, application of BC for packaging remains limited due to its hygroscopic nature, poor food preservation capabilities, and low optical transparency. In this study, a novel in-situ spraying method for chitosan (CS) encapsulation was developed to fabricate BC/CS hybrid structure layer by layer. The resulting composites exhibit effective antimicrobial activity against both Gram-positive and Gram-negative (> 75 %) bacteria, ensuring food preservation and safety. The BC/CS composites were modified through mercerization and heat drying (mBC/CS), transforming the cellulose crystal structure from cellulose I to the more stable cellulose II and inducing the alignment of a compact structure. Following waterborne polyurethane (WPU) coating, the mBC/CS/WPU composites acquired hydrophobic and heat-sealable properties, along with an 80 % reduction in haze and light transmittance exceeding 85 %. Further, they exhibited exceptional mechanical properties, including an ultimate tensile strength exceeding 200 MPa and omnidirectional flexibility. These composites could also preserve the freshness of sliced apples (< 20 % weight loss) and poached chicken (< 3 % weight loss) after one week of storage, comparable to commercial zipper bags, and also prevent food contamination. Notably, the mBC/CS/WPU composites displayed no ecotoxicity during decomposition and degraded completely within 60 days in soil. This study provides a valuable framework for functionalizing BC-based materials, promoting sustainable packaging, and contributing to the mitigation of plastic pollution.

Pectin blended with cellulose nanofiber (CNF) sourced from wood pulp has excellent potential for modified atmosphere packaging (MAP), as demonstrated with refrigerated or sliced fruits enclosed in parchment coated with pectin-CNF composites. Addition of sodium borate (NaB) augments the antioxidant capacity of the composite, most likely through the generation of unsaturated pectic acid units. Packaging materials coated with pectin-CNF-NaB composites demonstrate better humidity regulation in refrigerated spaces over a 3-week period relative to uncoated controls (50% less variation), with improved preservation of strawberries as well as a reduction in the oxidative browning of sliced apples. Pectin-CNF films are both biorenewable and biodegradable as confirmed by their extensive decomposition in soil over several weeks, establishing their potential as a sustainable MAP material. Lastly, self-standing films are mechanically robust at 80% RH with tensile strength and toughness as high as 150 MPa and 8.5 MJ/m2 respectively. These values are on par with other bioplastic composites and support the practical utility of pectin-CNF composites in functional packaging applications.

To enhance the barrier performance of biomass films, carboxymethyl cellulose (CMC) was combined with montmorillonite (MMT) modified by stearyltrimethylammonium bromide (STAB) and loaded with Fe3O4 particles as a nano-filler, and a CMC/m-OMMT mulch film was fabricated using magnetic field orientation. The characterization of m-OMMT was conducted through Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and vibrating sample magnetometry (VSM), which confirmed the successful intercalation of STAB into the MMT structure, along with the effective loading of Fe3O4 particles onto the MMT matrix. A comprehensive investigation into the mechanical properties of CMC/m-OMMT films revealed that, in the dry state, the films exhibited a tensile strength of 29 MPa and an elongation at break of 64 %. A series of barrier performance tests were conducted on the films. The findings demonstrated that the incorporation of MMT and the application of a magnetic field substantially enhanced the water contact angle, increasing it from 86 degrees to 112 degrees. Additionally, water vapor permeability increased by approximately 30 %, soil erosion was reduced by about 22 %, and UV resistance was notably improved by 94 %. Moreover, scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and biodegradation tests on the CMC/m-OMMT/40mT films revealed that the magnetic field effectively oriented the MMT nanosheets within the composite matrix. This study presents a novel approach for enhancing the barrier properties of biomass-based mulch films.

The extensive use of petroleum-based plastics has resulted in critical energy and environmental challenges, driving the pursuit of sustainable and biodegradable bioplastics as ideal alternatives. However, the development of functional bioplastics with superior mechanical strength, water stability, and thermal stability remains a formidable challenge. Herein, inspired by the nacre, a cellulose-based bioplastic was designed with a unique layered architecture and enhanced interfacial interactions,achieved through the self-assembly of carboxymethyl cellulose (CMC) and nano-montmorillonite, while simultaneously forming a chemically and physically double-crosslinked network under the action of TiO2 nanoparticles and citric acid. The resulting bioplastic demonstrated excellent mechanical performance, with the tensile strength reaching 106.83 MPa, representing a 220.09 % improvement over pure CMC-based bioplastic and surpassing the tensile strength of other CMC-based films. Alongside mechanical prowess, it exhibited exceptional water resistance (water absorption reduced to 42.88 %), thermal stability and UV shielding. Furthermore, it was biodegradable and environmentally benign, capable of achieving complete degradation in the soil within three months. This biomimetic strategy provided a novel approach for developing competitive cellulose-based bioplastics, offering a promising alternative to petroleum-derived plastics for everyday applications.

The growing demand for sustainable and environment-friendly materials has driven extensive research on biopolymers for applications in agriculture, food science, and environmental remediation. Among these, nanocellulose-hydrogel hybrids (NC-HHs) have gained significant attention as an innovative class of bio-based materials that uniquely combine the remarkable physicochemical properties of nanocellulose with the functional versatility of hydrogels. These hybrids are characterised by exceptional water retention, mechanical strength and biodegradability, enabling advances in precision agriculture, smart food preservation and contaminant remediation. This review provides a comprehensive understanding of the synthesis, properties, and multifunctional applications of NC-HHs, emphasising their innovative role in sustainability. In agriculture, NCHHs enhance soil moisture retention, support plant growth, and serve as carriers for controlled-release fertilizers, optimizing water and nutrient use efficiency. In the food industry, they enable intelligent packaging solutions that extend shelf life, monitor food freshness, and inhibit microbial growth. Additionally, NC-HHs present groundbreaking strategies for environmental remediation by effectively immobilizing pollutants in water and soil. Beyond summarizing recent advances, this review presents an in-depth mechanistic perspective on the interactions between NC and HH, critically evaluating their structure-property relationships, functional adaptability and application-specific performance. By integrating recent advances in nanocellulose functionalisation, polymer chemistry and the development of responsive hydrogels, this review critically examines the key technological innovations and future prospects of NC-HHs, underscoring their transformative potential in addressing global challenges related to food security, environmental sustainability, and sustainable agricultural practices.